Vitamin C: helper of our immunity? Part 1: all about the immune system

Short answer: it is absolutely necessary, but it won’t be your expected “immune booster”.

During this strange time of a pandemic, one simple, highly accessible, yet seemingly so powerful nutraceutical substance had been proposed as a treatment in the battle against COVID-19: vitamin CCurrently, many ongoing trials are to find out its true efficacy. Recently, we’ve seen a lot of promotions on vitamin C ingestions from oral supplementations to IV drips, and wondered to ourselves: how effective is vitamin C in upping our immunity against illnesses? Surely, vitamin C had been touted with benefits of curing the common cold (and honestly, we’ve all done it and it kinda works?), but to see if that’s due to its actual ability or mere placebo is another story. With vitamin C being an essential nutrient for the human body, most of its benefits can boil down to its biochemical effects in the areas including [1][2]:

  • antioxidant effects;
  • acting as a co-factor for many enzymatic reactions in the body;
  • epigenetic regulations.

Now translating that into actual observable changes, vitamin C had been shown to have the following overall benefits [1][3]:

  • reduces inflammation
  • fights cancers
  • prevention and protection against infections
  • wound healing and tissue repair (collagen synthesis)
  • better skin (again, collagen synthesis)
  • higher iron absorption from diets
  • better neural functions
  • increasing fat metabolism
  • maintenance of overall health

We think you get the idea: vitamin C absolutely helps with our bodily functions. Indeed, vitamin C deficiency is directly causative of scurvy, a nasty disease with symptoms including gum disease, fatigue, bleeding from the skin, anemia, etc [3][4]. The good news? You can easily ingest enough vitamin C daily by just consuming your recommended amount of fruits and veggies. If you want to learn more about the top immune benefits of vitamin C, then read along 👇👇👇

Vitamin C: the substance

Here, we want to start with the definition of an essential nutrient:

A nutrient is considered essential, when it is necessary for the normal/physiological functions of the body (in this case, our human bodies) but cannot be produced in sufficient quantities (or at all!) by the body itself [5].

Vitamin C in its bioactive salt form (known as “ascorbate”) is an essential nutrient for the human body, as it 1) is necessary for our bodily functions; and 2) our bodies lack the enzyme (L-gulonolactone oxidase) to produce it [3][6]. Luckily, vitamin C is readily available (thank goodness) in many foods and can also be ingested via supplementation (we’re aware of the controversy on this and will be discussing it right down below in the last section!).

Vitamin C Against Infections

While a quick Google search would return to you a whole list of the benefits of vitamin C intake, we believe that the top benefits of vitamin C can be attributed to its positive effects on the human body’s immune system (While we try to refrain from words like “boosting immunity” since the point of taking vitamin C is to maintain a strong immune system, you bet it’s true that vitamin C does contribute greatly.). Vitamin C is a rather multifaceted component in the trilogy of our immunity against infections:

  • prevention of infections (thicker skin!) [7][8]
  • fight against infections (activation of immune cells) [1][4][9]
  • protection from future infections (maintenance of good immune health, antioxidant, and antibody production)[1][2][4]

To start off, vitamin C is a cofactor (aka team-player) in the process of collagen production. Collagen is a protein, and it is also one of the major building blocks of our skin, tendons, ligaments, organs, bones, or really, any soft parts of our body. Vitamin C is directly involved in the production of collagen at the last stage to stabilize collagen structure [3][10]. Because of the participation of vitamin C in collagen production, clinical studies had found that vitamin C can aid in wound healing [10]. Indeed, vitamin C had been found to accumulate in skin cells in relatively large quantity, showing that it is naturally collected in these areas to perform certain functions, including working as an antioxidant against outer environmental damages [7]. This is important as our skins are constantly being challenged by harms from the UV light, the cold, the heat, and the toxins, all of which can result in oxidative damages to our own cells [7][8]. Vitamin C in this case acts as a protective agent by “neutralizing” the oxidative effects from these outer shocks, and creating a safe environment for our skin cells to continue doing what they do best — guard against pathogens.

If by any chance any invaders do make it in our body, there goes our bodies’ second stage of defence: activation of the immune system. We’ll let you in on a secret: our immune system has two stages of activation, which are called the innate immunity and adaptive immunity [11]. To understand the concept of the two immune stages, think of a case if someone’s home was invaded but the owner had defended successfully — first, there goes the fight to kick the intruder out (this is the innate immunity)! When the fight is over and the house owner had successfully secured the house, he/she would likely build a stronger defence around the house, perhaps some more fences, a security camera, and maybe pick up some self-defence skills (this is the adaptive immunity). Likewise in our bodies, some cells are focused more on kicking the butts of those uninvited microbes during an infection, while some other cells are better at cleaning up the mess and learning tricks to stop the same invaders — that’s if they ever dare to come again the second round (take a look at the below image for a list immune cells).

Immune cells involved in the innate and adaptive responses (image generated with Biorender).

Vitamin C strengthens our immunity by activating and helping the cellular functions of cells in both the innate and adaptive stages of our immunity: the cells it helps out include neutrophils, macrophages, natural killer cells, phagocytes, T cells, and B cells, etc., essentially covering most steps of the immune reaction [1].[9].

(As a side note, inflammation is caused by the actions of our immune system as well — and vitamin C helps reduce inflammation too! [9]).

As you can see, vitamin C plays a signifiant role in the maintenance of our good health, especially in the immune system. In part two of the vitamin C series, we’ll be discussing the bioavailability, absorption and the different form of vitamin C intake. We’ll also show you the exact food items and how much of them to take daily to achieve your vitamin C goal (it’s quite easy!)! 🤗To be continued… 

[1] Carr, A., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients9(11), 1211. doi: 10.3390/nu9111211

[2] Ang, A., Pullar, J. M., Currie, M. J., & Vissers, M. C. (2018). Vitamin C and immune cell function in inflammation and cancer. Biochemical Society Transactions46(5), 1147–1159. doi: 10.1042/bst20180169

[3] Lykkesfeldt, J., Michels, A. J., & Frei, B. (2014). Vitamin C. Advances in nutrition (Bethesda, Md.)5(1), 16–18.

[4] Chambial, S., Dwivedi, S., Shukla, K. K., John, P. J., & Sharma, P. (2013). Vitamin C in Disease Prevention and Cure: An Overview. Indian Journal of Clinical Biochemistry28(4), 314–328. doi: 10.1007/s12291-013-0375-3


[6] Figueroa-Méndez, R., & Rivas-Arancibia, S. (2015). Vitamin C in Health and Disease: Its Role in the Metabolism of Cells and Redox State in the Brain. Frontiers in Physiology6. doi: 10.3389/fphys.2015.00397

[7] The Roles of Vitamin C in Skin Health. (2017). Nutrients9(8), 866. doi: 10.3390/nu9080866

[8] Telang P. S. (2013). Vitamin C in dermatology. Indian dermatology online journal4(2), 143–146.

[9] Sorice, A., Guerriero, E., Capone, F., Colonna, G., Castello, G., & Costantini, S. (2014). Ascorbic Acid: Its Role in Immune System and Chronic Inflammation Diseases. Mini-Reviews in Medicinal Chemistry14(5), 444–452. doi: 10.2174/1389557514666140428112602

[10] Dephillipo, N. N., Aman, Z. S., Kennedy, M. I., Begley, J., Moatshe, G., & Laprade, R. F. (2018). Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries: A Systematic Review. Orthopaedic Journal of Sports Medicine6(10), 232596711880454. doi: 10.1177/2325967118804544